1. Field of the Invention
The present invention relates to therapeutic footwear and, more particularly, to a self-compressive massage sock useful for patients susceptible to foot problems resulting from diabetes or other circulatory foot conditions.
2. Discussion of the Related Art
Sitting stationary for long periods of time leads to an impaired venous return in the lower limbs that engenders local gatherings of blood. This causes swelling and discomfort around the ankles. Moreover, the effects of long term sitting can be serious inasmuch as stasis can lead to the formation of blood clots, pulmonary embolisms, etc. Certain segments of the population are more prone to these symptoms, including the elderly and those with diabetes.
Diabetic neuropathies can be classified as peripheral, autonomic, proximal, and focal, each of which affects different parts of the body in different ways. Peripheral neuropathy (or distal symmetric neuropathy) tends to affect the arms and legs with circulation problems. Symptoms include either pain or loss of feeling in the toes, feet, legs, hands, and arms. Blisters and sores may appear on numb areas of the foot, and the loss of sensation in the feet means that such sores or injuries may not be noticed and may become ulcerated or infected. If foot injuries are not treated promptly, the infection may spread to the bone. Indeed, cardiovascular complications resulting from diabetes are the leading cause of lower-limb amputations in diabetics.
It is well-known that diminished circulation in the extremities and particularly the feet can be treated by massage therapy. Consequently, a variety of massaging socks, stockings, shoes and foot pads currently exist. However, these rely primarily on friction to impart the massage, which does little for circulation.
Compression is a more appropriate therapy for those seeking to increase circulation, and compressive devices seeking to prevent or reduce thrombosis have been proposed. For example, an inflatable compression garment is disclosed in GB-A-2271060, and an ambulatory pneumatic compression device is disclosed in GB-A-2263405. Blood circulation in a limb is stimulated by a periodically inflatable sheet which is wrapped around a patient's foot. Unfortunately, this is cumbersome to apply and requires an external pressure source. GB-A-2263405 discloses an orthopedic shoe connected to cells wrapped around the calf and ankle of a user and operable to exert a pumping effect to the cells as the user walks. When the patient walks air is moved from air cells in the heel to cells in the ankle and calf. This sequentially increases the pressure exerted on the patient's ankle and calf, promoting peripheral circulation to treat leg ulcers. While the concept is valid the implementation lacks effectiveness because it relies on constriction which occurs only at the heel strike and uniformly around two collar-like pads wrapped around the ankle. The effect is somewhat less than a massage which should be applied with a kneading, non-constricting undulating (wavelike) pattern-compression motion. Moreover, the user is constrained to wearing just one pair of shoes.
Similarly, U.S. Pat. No. 6,589,194 to Calderon et al. (C-Boot Ltd) issued Jul. 8, 2003 shows a self-powered compression device for promoting circulation and therapeutic compression. The device is self-powered, employing a plurality of inflatable sleeves arranged sequentially for applying compression to a body or limb, and a pump, a piping system and a bandage or boot to enclose the sleeves and pump in their its entirety. The device uses self-generated pressure from walking in promoting circulation for treatment of lymphatic and traumatic edemas, venous disorders, limb ulcers, varicose veins, muscle fatigue, sports medicine, cellulite treatment, diabetic feet, and simple feet massage for recreation or cosmetic enhancements. This device is still rather cumbersome and relies on pure constriction, not a non-constricting variable pattern-compression motion.
U.S. Pat. No. 6,409,691 to Dakin et al. (Daos Limited) issued Jun. 25, 2002 shows a liquid brace with a number of flexible compression bags pressurized by a pump, which may be driven by muscle contracting or weight-bearing activities. The pump may provide a dynamic, oscillatory pressure. The bags are separated by valves allowing the liquid to flow in a controlled manner through the bags.
There are also a variety of inflatable orthotics, such as inner soles with inflated cushions at either the toe and heel areas. The cushions circulate air and ventilate the shoe or boot during walking activities. See, for instance, U.S. Pat. Nos. 3,180,039, 2,716,293 and 1,213,941. However, the inflating pads are for support and do nothing for circulation.
More recently, Nike™ has introduced a sole with integral self-inflating pads. The pads are inflated by an on-board finger pump. Similarly, U.S. Pat. No. 5,846,063 to Lakic discloses an air pump and relief valve assembly that can be sealed to a flat sheet of plastic and embedded in the sole.
It would be greatly advantageous to provide a therapeutic massage sock self-powered by an embedded pump to provide a self-compressive non-constricting and yet deep-kneading, non-constricting undulating (wavelike) pattern-compression massage action, which can be worn with virtually any conventional pair of shoes, to benefit patients susceptible to foot problems resulting from diabetes or other circulatory foot conditions.